Proc. of the IEEE/OES Seventh Working Conference on Current Measurement Technology

EddyNet: A Measurement Program for Collecting Real-Time Current Profiles from the

Steven P. Anderson Horizon Marine, Inc. 15 Creek Road Marion, MA 02738 (508) 748-1860 [email protected]

Cortis K. Cooper ChevronTexaco, Exploration & Production Technology Co. 6001 Bollinger Canyon Rd, L-4240 San Ramon, CA 94583

David B. Driver BP America Inc. P.O. Box 3092 Houston, TX 77253-3092

Jan van Smirren Fugro GEOS Inc. 6100 Hillcroft (77081) PO Box 740010 Houston, TX 77274

Abstract—This paper describes the development and Eddy Joint Industry Project (EJIP) is a collaborative implementation of a measurement network that provides real- program, supported by several companies, that strives to time ocean current profiles collected from drilling rigs, effectively utilize limited resources to better observe and oceanographic survey vessels, and production facilities located understand the powerful currents found in the deepwater in the Gulf of Mexico. The Eddy Joint Industry Project Gulf. This paper reports on a recent EJIP initiative to developed the program, named EddyNet. This real-time develop a real-time measurement network that ties together network of observations improves the ability to analyze ocean current profile information collected by sites around the Gulf currents in the Gulf of Mexico and ultimately to support the and makes the data readily available to operators and forecasters. operational needs of deepwater hydrocarbon exploration and production. In addition, EddyNet provides a centralized II. BACKGROUND oceanographic database that can be used to develop environmental design criteria. The Loop Current (LC) is an energetic current of warm water that enters the Gulf of Mexico through the Yucatan I. INTRODUCTION Strait then loops around and exits the Gulf through the Florida Strait. Its position and strength change over time. Deepwater exploration and production of oil and gas is a Once or twice a year, the LC extends far north, and the loop complex endeavor that requires extensive planning and becomes so tight that it becomes a closed circulation, forming mitigation of risks to achieve success. One of the most an anticyclonic ring or eddy. Like the LC, these Loop productive deepwater regions is the Gulf of Mexico. It is also Current eddies (LCE) also have strong currents, but unlike a region where deepwater fields are collocated with regions the LC, they are not constrained to the eastern Gulf. Instead, of strong ocean currents especially those associated with the they are free to move west and north where they often Loop Current and its anticyclonic eddies. A good interfere with deepwater hydrocarbon exploration and understanding of these currents is crucial to safe operations production operations in the northern and western Gulf. Oil and design. industry activity in the Gulf continues to expand into deeper

0-7803-7813-X/03/$17.00 ©2003 IEEE

Proc. of the IEEE/OES Seventh Working Conference on Current Measurement Technology water. As it does, it is increasingly exposed to the Loop monitor ocean current profiles locally. In addition, survey Current and associated eddies. vessels are sometimes equipped with ADCPs to monitor regions of strong currents “upstream” of a rig during critical Offshore operators in the Gulf often rely on a commercial operations. While some manual real-time data sharing of program called “Eddy Watch” to obtain operational these data is occurring, it is not consistent nor efficient. monitoring and tracking of the LC and LCE. This program, Finally, much of the data is lost after the operational value run by Horizon Marine, relies on data from air-deployed has been extracted despite the fact that the data is often useful drifting buoys combined with remote sensing and a few field for later design of production facilities. observations to track LC and LCE fronts and regions of strong currents. However, this system is somewhat limited In summary, EddyNet was designed to integrate existing because it provides regional scale analyses and tracks only ADCPs into a network that could be accessed in real-time surface currents (Figure 1). Historical data and experience with the goal of have shown that LC and LCE current profiles can vary 1. improving LC and LCE monitoring and forecasting substantially and this has a major effect on the forces for engineering operations, imposed on the rigs. In addition, strong mid-water current 2. documenting other potentially strong current events, events of unknown origin have been observed. These have 3. archiving data so it is not lost and is ready for little or no direct surface signature so are often undetected by comprehensive re-analysis,

Figure 1. A chart showing the location of Millennium Eddy on 24 March 2001. Also shown are the seven-day buoy tracks and locations of active or planned offshore exploration and production sites.

29°N

28°N

27°N

26°N

25°N Buoy Drift Track

Offshore Sites 24°N Frontal Features

94°W 92°W 90°W 88°W

the standard Eddy Watch measurement devices. 4. providing real-time surface currents in support of oil spill tracking and search and rescue operations. Operators also use Acoustic Doppler Current Profilers (ADCPs) deployed on their drillships and platforms to EddyNet consists of an offshore component that is located

Proc. of the IEEE/OES Seventh Working Conference on Current Measurement Technology

at each offshore data collection site and an onshore from a serial data stream or from network file sharing, component that collects and manages the data collection leaving the existing computer system and software intact. and distribution.

III. OFFSHORE COMPONENT To monitor serial data, a serial port splitter is used to allow a second computer running RTADCP to listen to the serial The offshore component of EddyNet includes the Real- data stream coming directly from the ADCP to the primary Time ADCP (RTADCP) software developed specifically for ADCP control/display computer. Serial data can also be EddyNet. RTADCP accesses data from the ADCP at user- transmitted using RDI Transect software that is configured defined intervals, adds additional information (such as site with the "ensemble-out" function to send data out through a name, water depth, and position), and formats the data into second serial port on the primary ADCP control computer to RD Instruments Broadband ADCP file format. RTADCP a second computer with the RTADCP software. then transmits the data files to the onshore EddyNet server through existing Internet connections or a stand-alone Iridium Alternately, RTADCP can be configured to monitor raw satellite data services link (Figure 2). ADCP binary files through network file sharing. In this case, the primary ADCP control computer is configured to share The first requirement for RTADCP was to assure that the the directory containing the ADCP data files being collected. new software did not noticeably alter the existing ADCP RTADCP is then configured to monitor this directory monitoring system. The operators wanted to be sure the remotely and check for new ensembles at user defined ADCP systems continued to be reliable and accessible to intervals. (Note that this configuration is not possible if the individuals in the field. Thus, RTADCP is configured to primary control computer is operating in a DOS acquire the raw ADCP data on a secondary computer, either environment.)

Data Transmission Stand-alone Iridium Satellite Modem or Existing Ku-Band Network System

FTP Server Computer running RTADCP software

EddyNet Data Processor Archive

Broadband ADCP Data Processing Web Server Center Drillship, Survey Vessel, or Platform Web Site Real-time graphics and data

Forecasters and EddyNet Members

Figure 2. Flow diagram showing integration of EddyNet offshore and onshore components.

Proc. of the IEEE/OES Seventh Working Conference on Current Measurement Technology

Figure 3. Example of ADCP data from RDI 38 kHz ADCP operated by BP America Inc. and deployed on the Discoverer Enterprise.

over an independent network. In the case where existing The second requirement for RTADCP was to use a data networks are unavailable, an Iridium Satellite LLC data format that included site-specific meta-data while transmission system can be used. The Iridium system uses a maintaining compatibility with existing RDI data analysis Motorola 9500 Portable Phone, Motorola 9570 Portable software. The decision was made to use the RDI Broadband Dock, and a data kit. Data is transmitted using either dial-up data format for the ensemble data where each ensemble or Iridium direct Internet services. includes a header, a fixed leader, a variable leader, and velocity profile data as described in the RDI Technical IV. ONSHORE COMPONENT Manual [1]. RTADCP then creates EddyNet specific leader data that is appended to each ensemble. The EddyNet leader The onshore component of EddyNet includes the software, block includes ancillary data including the location of hardware, and network resources required to acquire, archive, measurements, the type of instrument, the platform name, the analyze, visualize, and distribute the real-time data. It also operator's name, the water depth, and the time zone used for includes the EddyNet program administration and time stamping. A unique leader block ID number identifies accounting. the EddyNet leader block. In this configuration, existing RDI software is able to display the current profile data in EddyNet The EddyNet server continuously receives and archives data files; however, it will ignore information within the data from the offshore sites. Most of the data is received EddyNet leader block. directly through the Internet using a file transmission protocol (ftp) server. The EddyNet ftp server is located at an Internet After acquiring and reformatting the original data, the data processing center that provides 24-hour support and RTADCP software transmits that data to the server located server redundancy. Throughout the day, the EddyNet server onshore. Many of the offshore drillships and platforms have copies new data files to an offsite data archive and to the dedicated communications systems. RTADCP can use these EddyNet processing computer. network systems to deliver the data through the Internet using an ftp client. However, there are situations when this The EddyNet processor performs preliminary automated network does not exist or is unavailable due to network quality control on the incoming data. The processor sends out security reasons. In this case, there are two options for data email alerts to the EddyNet administrator and the operator if telemetry. If a Ku-band satellite communications systems is incoming data fails Q/C or no real-time data is received from in operation at the remote site but not directly available to the a specific site. The EddyNet processor also provides secure ADCP system, it may be possible to fit an additional card into website access to real-time current profiles with links to both the communications multiplexer and transmit ADCP data raw data and graphical data displays from each site. Finally,

Proc. of the IEEE/OES Seventh Working Conference on Current Measurement Technology the EddyNet processor calculates daily averaged surface currents from each site for use by eddy forecasting services. Figure 3 shows an example of the ADCP data collected on the Discoverer Enterprise by BP America. The site uses a 38 EddyNet participants provide either data from their own kHz ADCP. The figure shows nine days of data and the measurement systems or pay a subscription fee. Participants shading indicates current speed with lighter shades can access this data through the website as often as they like. corresponding to higher speeds. Reliable current profiles At the end of each month, the EddyNet Administrator saves extend down below 800 m. Apparent in the data is the all the archived data from that month to CDROM. A copy of upward phase propagation of near-inertial waves in a the archived data is mailed to each of the EddyNet downward propagating wave group. participants. The EddyNet Administrator also collects funds from subscription members and forecasters and redistributes V. CONCLUSIONS the funds to the data members to help pay for ADCP operation and communication costs. The whole system has proven to be reliable, and over 16 months of ADCP data were collected during 2002. There V. PROGRAM IMPLEMENTATION were very few problems encountered with the system during the first months of operation. The major hurdle for operators The development of the onshore and offshore components has been working with their Information Technology occurred during the first quarter of 2002. The first site came department to receive permission to connect to the company online with real-time data transmission in May 2002 and was networks and to transmit data from the offshore sites. The operated by Marathon Oil Company. The ADCP was number of participants is expected to increase during the deployed in the East Break lease area onboard Noble coming year. A real demonstration of the value of EddyNet Corporation's a semi-submersible rig named Amos Runner. will come during the first half of 2003 when the next major This system utilized Iridium communications and an RDI Loop Current Eddy is forecast to reach the northern Gulf. 75kHz ADCP.

ChevronTexaco brought online the second and third ACKNOWLEDGEMENTS EddyNet sites during the summer. The ADCPs were located on their Genesis site in the Green Canyon lease area and The Eddy Joint Industry Project developed the EddyNet concept and onboard the Transocean Discoverer Deep Seas drillship supported development of the components. Kenneth J. Schaudt operating in Atwater Valley and Green Canyon. In the fall, of Marathon Oil Company provided comments on this manuscript. BP America starting sending data from an RDI 38 kHz Marathon Oil Company is an EddyNet data participant. Alexis Lugo ADCP on the Transocean Discoverer Enterprise drillship Fernandez at the Minerals Management Service provided encouragement and operating in . All of these systems utilize support for EddyNet. existing communications networks. REFERENCES Forecasters are now making regular use of EddyNet ADCP data to help with LC and LCE tracking. The Mineral [1] RD Instruments, “Workhorse Commands and Output Data Format,” Management Service has joined EddyNet as a subscription 2001. member and is using some of the archived data to help develop deepwater oil spill models.